Amphiphilic siloxane-containing (meth)acrylamides and uses thereof

ABSTRACT

The invention provides an amphiphilic siloxane-containing (meth)acrylamide which comprises one sole (meth)acrylamido group, one sole tris(trimethylsiloxy)silyl group, and one polyethylene glycol segment which is either dangling polymer chain or a hydrophilic linker between the (meth)acrylamido group and the tris(trimethylsiloxy)silyl group. The present invention is also related to a polymer, an actinically-crosslinkable silicone-containing prepolymer, a silicone hydrogel polymeric material, or a silicone hydrogel contact lens, which comprises monomeric units derived from an amphiphilic siloxane-containing (meth)acrylamido group, one tris(trimethylsiloxy)silyl group of the invention. In addition, the invention provides a method for making silicone hydrogel contact lenses using a water-based lens-forming formulation comprising an amphiphilic siloxane-containing (meth)acrylamido group, one tris(trimethylsiloxy)silyl group of the invention and/or an actinically-crosslinkable silicone-containing prepolymer of the invention.

This application claims the benefits under 35 USC §119 (e) of U.S. provisional application No. 61/737,181 filed Dec. 14, 2012, incorporated by reference in its entirety.

The present invention is related to a class of amphiphilic siloxane-containing (meth)acrylamides having a polyethylene glycol (“PEG”) segment and a bulky siloxane group. The present invention is also related to medical devices including contact lenses made from a composition comprising an amphiphilic siloxane-containing (meth)acrylamide of the invention. In addition, the present invention is related to a method for making silicone hydrogel contact lenses.

BACKGROUND

In recent years, soft silicone hydrogel contact lenses become more and more popular because of their high oxygen permeability and comfort. “Soft” contact lenses can conform closely to the shape of the eye, so oxygen cannot easily circumvent the lens. Soft contact lenses must allow oxygen from the surrounding air (i.e., oxygen) to reach the cornea because the cornea does not receive oxygen from the blood supply like other tissue. If sufficient oxygen does not reach the cornea, corneal swelling occurs. Extended periods of oxygen deprivation cause the undesirable growth of blood vessels in the cornea. By having high oxygen permeability, a silicone hydrogel contact lens allows sufficient oxygen permeate through the lens to the cornea and to have minimal adverse effects on corneal health.

Typically, silicone hydrogel contact lenses are produced according to a cast molding technique involving use of disposable or reusable molds and a silicone hydrogel lens formulation (i.e., a mixture of vinylic monomers and/or vinylic macromers). A silicone hydrogel lens formulation often comprises a bulky siloxane-containing vinylic monomer, such as, for example, a vinylic monomer having a tris(trialkylsilyloxy)silylalkyl group (e.g., tris(trimethylsilyloxy)-silylpropyl acrylate, tris(trimethylsilyloxy)-silylpropyl methacrylate, tris(trimethylsilyloxy)-silylpropyl acryalmide, tris(trimethylsilyloxy)-silylpropyl methacrylamide, tris-(trimethylsiloxysilyl)propylvinyl carbamate, etc.). It is reported that such a bulky siloxane-containing vinylic monomer is critical to the elimination of optical defects derived from handling during manufacturing, especially when curing the monomer mixture in a mold within a relatively short time (e.g., less than about 300 seconds) with a UV light. When such a bulky siloxane-containing vinylic monomer is eliminated from a monomer mixture for making silicone hydrogel contact lenses, resultant lenses may develop permanent deformations (optics defects) due to handling. But, when such a bulky siloxane-containing vinylic monomer is present, resultant lenses exhibit a ‘healing’ effect that eliminated the optical defects (i.e., the folding marks become transient and can disappear after a short time period, e.g., about 15 minutes or less).

However, most of available bulky-siloxane-containing vinylic monomers are hydrophobic and not suitable for making water-based silicone hydrogel lens formulations. In addition, unpolymerized bulky siloxane-containing vinylic monomers must be removed from molded lenses by using an organic solvent in a lens extraction process. Such lens extraction process increases the production cost and is not environmentally friendly.

Therefore, there is still a need for amphiphilic siloxane-containing vinylic monomers which have adequate solubility in water and can be used in an environmentally-friendly lens production process.

SUMMARY OF THE INVENTION

In one aspect, the invention provides an amphiphilic siloxane-containing (meth)acrylamide, which comprises one sole (meth)acrylamido group; one sole bulky siloxane group; and one hydrophilic polyethylene glycol segment which is either a dangling polymer chain or a hydrophilic linker between the (meth)acrylamido group and the bulky siloxane group.

The present invention, in another aspect, provides a polymer (preferably an actinically-crosslinkable prepolymer or silicone hydrogel material) which is a polymerization product of a polymerizable composition comprising an amphiphilic siloxane-containing (meth)acrylamide of the invention.

The present invention, in a further aspect, provides a medical device, preferably an ophthalmic device, more preferably a silicone hydrogel contact lens, which comprises a polymeric material comprising monomeric units derived from an amphiphilic siloxane-containing (meth)acrylamide of the invention.

The present invention, in still a further aspect, provides a method for producing silicone hydrogel contact lenses. The method comprises the steps of: introducing a lens-forming formulation into a mold for making contact lenses, wherein the lens-forming formulation comprises (a) a solvent selected from the group consisting of water, 1,2-propylene glycol, a polyethyleneglycol having a molecular weight of about 400 Daltons or less, and mixtures thereof, (b) at least one amphiphilic siloxane-containing (meth)acrylamide of the invention and/or at least one actinically-crosslinkable prepolymer of the invention, and (c) at least one component selected from the group consisting of a hydrophilic vinylic monomer, a hydrophilized polysiloxane-containing crosslinker, a hydrophilic crosslinker, a photoinitiator, a thermal initiator, a UV-absorbing vinylic monomer, a visibility tinting agent, an antimicrobial agent, a bioactive agent, a leachable lubricant, a leachable tear-stabilizing agent, and mixtures thereof; polymerizing the lens-forming formulation in the mold to form a silicone hydrogel contact lens, wherein the formed silicone hydrogel contact lens has a water content of from about 20% to about 75% (preferably from about 25% to about 70%, more preferably from about 30% to about 65%) by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers (preferably at least about 50 barrers, more preferably at least about 60 barrers, and even more preferably at least about 70 barrers), and an elastic modulus of from about 0.1 MPa to about 2.0 MPa, preferably from about 0.2 MPa to about 1.5 MPa, more preferably from about 0.3 MPa to about 1.2 MPa, even more preferably from about 0.4 MPa to about 1.0 MPa.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the laboratory procedures are well known and commonly employed in the art. Conventional methods are used for these procedures, such as those provided in the art and various general references. Where a term is provided in the singular, the inventors also contemplate the plural of that term. The nomenclature used herein and the laboratory procedures described below are those well known and commonly employed in the art.

“About” as used herein means that a number referred to as “about” comprises the recited number plus or minus 1-10% of that recited number.

A “medical device” refers to a device having surfaces that contact tissue, blood, or other bodily fluids of patients in the course of their operation. Exemplary medical devices include: (1) extracorporeal devices for use in surgery such as blood oxygenators, blood pumps, blood sensors, tubing used to carry blood and the like which contact blood which is then returned to the patient; (2) prostheses implanted in a human or animal body such as vascular grafts, stents, pacemaker leads, heart valves, and the like that are implanted in blood vessels or in the heart; (3) devices for temporary intravascular use such as catheters, guide wires, and the like which are placed into blood vessels or the heart for purposes of monitoring or repair; and (4) ophthalmic devices.

An “ophthalmic device”, as used herein, refers to a contact lens (hard or soft), an intraocular lens, a corneal onlay, other ophthalmic devices (e.g., stents, glaucoma shunt, or the like) used on or about the eye or ocular vicinity.

“Contact Lens” refers to a structure that can be placed on or within a wearer's eye. A contact lens can correct, improve, or alter a user's eyesight, but that need not be the case. A contact lens can be of any appropriate material known in the art or later developed, and can be a soft lens, a hard lens, or a hybrid lens. A “silicone hydrogel contact lens” refers to a contact lens comprising a silicone hydrogel material.

A “hydrogel” or “hydrogel material” refers to a polymeric material which is insoluble in water, but can absorb at least 10 percent by weight of water when it is fully hydrated.

A “silicone hydrogel” refers to a silicone-containing hydrogel obtained by copolymerization of a polymerizable composition comprising at least one silicone-containing monomer or at least one silicone-containing macromer or at least one crosslinkable silicone-containing prepolymer.

“Hydrophilic,” as used herein, describes a material or portion thereof that will more readily associate with water than with lipids.

A “vinylic monomer” refers to a compound that has one sole ethylenically unsaturated group and is soluble in a solvent.

The term “soluble”, in reference to a compound or material in a solvent, means that the compound or material can be dissolved in the solvent to give a solution with a concentration of at least about 1% by weight at room temperature (i.e., a temperature of about 20° C. to about 30° C.).

The term “insoluble”, in reference to a compound or material in a solvent, means that the compound or material can be dissolved in the solvent to give a solution with a concentration of less than 0.005% by weight at room temperature (as defined above).

As used in this application, the term “ethylenically unsaturated group” is employed herein in a broad sense and is intended to encompass any groups containing at least one >C═C< group. Exemplary ethylenically unsaturated groups include without limitation (meth)acryloyl

allyl, vinyl, styrenyl, or other C═C containing groups.

As used in this application, the term “(meth)acrylamide” refers to methacrylamide and/or acrylamide and the term “(meth)acrylate” refers to methacrylate and/or acrylate.

As used herein, “actinically” in reference to curing, crosslinking or polymerizing of a polymerizable composition, a prepolymer or a material means that the curing (e.g., crosslinked and/or polymerized) is performed by actinic irradiation, such as, for example, UV irradiation, ionizing radiation (e.g. gamma ray or X-ray irradiation), microwave irradiation, and the like. Thermal curing or actinic curing methods are well-known to a person skilled in the art.

As used in this application, the term “hydrophilic vinylic monomer” refers to a vinylic monomer capable of forming a homopolymer that is water-soluble or can absorb at least 10 percent by weight water at room temperature.

As used in this application, the term “hydrophobic vinylic monomer” refers to a vinylic monomer which as a homopolymer typically yields a polymer that is insoluble in water and can absorb less than 10 percent by weight water at room temperature.

As used in this application, “TRIS” refers to a radical of —Si—[OSi(CH₃)₃]₃, namely the tris(trimethylsilyloxy)silyl group.

As used in this application, a “bulky siloxane group” refers to a monovalent radical of

in which B₁ is a trialkylsiloxy group of

A₁, A₂, A₃ and A₄ independent of one another are a C₁-C₆ alkyl, phenyl or benzyl; and r1 is an integer of 2 or 3.

A “prepolymer” refers to a starting polymer which contains two or more ethylenically unsaturated groups and can be cured (e.g., crosslinked) actinically or thermally to obtain a crosslinked polymer having a molecular weight much higher than the starting polymer.

As used in this application, the term “crosslinker” refers to a compound or polymer having at least two ethylenically unsaturated groups and being soluble in a solvent at room temperature. A “crosslinking agent” refers to a crosslinker having a molecular weight of about 700 Daltons or less.

A “polysiloxane” refers to a compound containing one sole polysiloxane segment of

in which R₁, R₂, R₃, R₄, R₅, R₆, R₇, and R₈ independently of one another, are C₁-C₁₀ alkyl, C₁-C₄ alkyl- or C₁-C₄-alkoxy-substituted phenyl, C₁-C₁₀ fluoroalkyl, C₁-C₁₀ fluoroether, C₆-C₁₈ aryl radical, -alk-(OC₂H₄)_(n1)—OR₉ in which alk is C₁-C₆-alkylene divalent radical, R₉ is H or C₁-C₄ alkyl and n1 is an integer from 1 to 10, m1 and m2 independently of each other are an integer of from 0 to 50 and (m1+m2) is from 1 to 100.

A “chain-extended polysiloxane” refers to a compound containing at least two polysiloxane segments separated by a linkage.

A “polysiloxane-containing crosslinker” refers to a compound having at least two ethylenically unsaturated groups and at least one polysiloxane segment.

As used in this application, the term “polymer” means a material formed by polymerizing/crosslinking one or more monomers or prepolymers.

As used in this application, the term “molecular weight” of a polymeric material (including monomeric or macromeric materials) refers to the weight-average molecular weight unless otherwise specifically noted or unless testing conditions indicate otherwise.

The term “alkyl” refers to a monovalent radical obtained by removing a hydrogen atom from a linear or branched alkane compound. An alkyl group (radical) forms one bond with one other group in an organic compound.

The term “alkylene” refers to a divalent radical obtained by removing one hydrogen atom from an alkyl. An alkylene group (or radical) forms two bonds with other groups in an organic compound.

In this application, the term “substituted” in reference to an alkylene divalent radical or an alkyl radical means that the alkylene divalent radical or the alkyl radical comprises at least one substituent which replaces one hydrogen atom of the alkylene or alkyl radical and is selected from the group consisting of hydroxyl, carboxyl, —NH₂, sulfhydryl, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio (alkyl sulfide), C₁-C₄ acylamino, C₁-C₄ alkylamino, di-C₁-C₄ alkylamino, halogen atom (Br or Cl), and combinations thereof.

The term “fluid” as used herein indicates that a material is capable of flowing like a liquid.

As used herein, the term “multiple” refers to three or more.

A free radical initiator can be either a photoinitiator or a thermal initiator. A “photoinitiator” refers to a compound that initiates free radical crosslinking/polymerizing reaction by the use of light. A “thermal initiator” refers to a compound that initiates radical crosslinking/polymerizing reaction by the use of heat energy.

A “UV-absorbing vinylic monomer” refers to a compound comprising an ethylenically-unsaturated group and a UV-absorbing moiety which can absorb or screen out UV radiation in the range from 200 nm to 400 nm as understood by a person skilled in the art.

A “spatial limitation of actinic radiation” refers to an act or process in which energy radiation in the form of rays is directed by, for example, a mask or screen or combinations thereof, to impinge, in a spatially restricted manner, onto an area having a well defined peripheral boundary. A spatial limitation of UV radiation is obtained by using a mask or screen having a radiation (e.g., UV) permeable region, a radiation (e.g., UV) impermeable region surrounding the radiation-permeable region, and a projection contour which is the boundary between the radiation-impermeable and radiation-permeable regions, as schematically illustrated in the drawings of U.S. Pat. No. 6,800,225 (FIGS. 1-11), and U.S. Pat. No. 6,627,124 (FIGS. 1-9), U.S. Pat. No. 7,384,590 (FIGS. 1-6), and U.S. Pat. No. 7,387,759 (FIGS. 1-6), all of which are incorporated by reference in their entireties. The mask or screen allows to spatially projects a beam of radiation (e.g., UV radiation) having a cross-sectional profile defined by the projection contour of the mask or screen. The projected beam of radiation (e.g., UV radiation) limits radiation (e.g., UV radiation) impinging on a lens-forming material located in the path of the projected beam from the first molding surface to the second molding surface of a mold. The resultant contact lens comprises an anterior surface defined by the first molding surface, an opposite posterior surface defined by the second molding surface, and a lens edge defined by the sectional profile of the projected UV beam (i.e., a spatial limitation of radiation). The radiation used for the crosslinking is radiation energy, especially UV radiation, gamma radiation, electron radiation or thermal radiation, the radiation energy preferably being in the form of a substantially parallel beam in order on the one hand to achieve good restriction and on the other hand efficient use of the energy.

The intrinsic “oxygen permeability”, Dk, of a material is the rate at which oxygen will pass through a material. As used in this application, the term “oxygen permeability (Dk)” in reference to a hydrogel (silicone or non-silicone) or a contact lens means a measured oxygen permeability (Dk) which is corrected for the surface resistance to oxygen flux caused by the boundary layer effect according to the procedures shown in Examples hereinafter. Oxygen permeability is conventionally expressed in units of barrers, where “barrer” is defined as [(cm³ oxygen)(mm)/(cm²)(sec)(mm Hg)]×10⁻¹⁰.

The “oxygen transmissibility”, Dk/t, of a lens or material is the rate at which oxygen will pass through a specific lens or material with an average thickness of t [in units of mm] over the area being measured. Oxygen transmissibility is conventionally expressed in units of barrers/mm, where “barrers/mm” is defined as [(cm³ oxygen)/(cm²)(sec)(mm Hg)]×10⁻⁹.

The term “water soluble or processable” in reference to a vinylic monomer or a prepolymer of the invention means that the vinylic monomer or prepolymer has a water solubility and/or dispersity of from about 1% to about 70% by weight at room temperature (about 22° C. to about 28° C.).

The term “water solubility and/or dispersity” in reference to a vinylic monomer or a prepolymer of the invention means the concentration (weight percentage) of the vinylic monomer or prepolymer dissolved and/or dispersed in water at room temperature (about 22° C. to about 28° C.) to form a transparent aqueous solution or a slightly hazy aqueous solution having a light transmissibility of 85% or greater in the range between 400 to 700 nm.

A “coupling reaction” in this patent application is intended to describe any reaction between a pair of matching functional groups in the presence or absence of a coupling agent to form covalent bonds or linkages under various reaction conditions well known to a person skilled in the art, such as, for example, oxidation-reduction conditions, dehydration condensation conditions, addition conditions, substitution (or displacement) conditions, Diels-Alder reaction conditions, cationic crosslinking conditions, ring-opening conditions, epoxy hardening conditions, and combinations thereof.

Non-limiting examples of coupling reactions under various reaction conditions between a pair of matching co-reactive functional groups selected from the group preferably consisting of amino group (—NHR′ in which R′ is H or C₁-C₄ alkyl), hydroxyl group, carboxyl group, acid halide group (—COX, X=Cl, Br, or I), acid anhydrate group, aldehyde group, azlactone group, isocyanate group, epoxy group, aziridine group, and thiol group, are given below for illustrative purposes. An amino group reacts with aldehyde group to form a Schiff base which may further be reduced; an amino group NHR′ reacts with an acid chloride or bromide group or with an acid anhydride group to form an amide linkage (—CO—NR′— with R′ as defined above); an amino group NHR′ reacts with an isocyanate group to form a urea linkage (—NR′—C(O)—NH— with R′ as defined above); an amino group NHR′ reacts with an epoxy or aziridine group to form an amine bond (—C—NR′— with R′ as defined above); an amino group NHR′ reacts (ring-opening) with an azlactone group to form an alkylene-diamido linkage (—C(O)NH-alkylene-C(O)NR′— with R′ as defined above); an amino group NHR′ reacts with a carboxylic acid group in the presence of a coupling agent carbodiimide (e.g., 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), N,N′-dicyclohexylcarbodiimide (DCC), 1-cylcohexyl-3-(2-morpholinoethyl)carbodiimide, diisopropyl carbodiimide, or mixtures thereof) to form an amide linkage; an amino group NHR′ reacts with a N-hydroxysuccinimide ester group to form an amide linkage; a hydroxyl reacts with an isocyanate to form a urethane linkage; a hydroxyl reacts with an epoxy or aziridine to form an ether linkage (—O—); a hydroxyl reacts with an acid chloride or bromide group or with an acid anhydride group to form an ester linkage; an hydroxyl group reacts with an azlactone group in the presence of a catalyst to form an amidoalkylenecarboxy linkage (—C(O)NH-alkylene-C(O)—O—); a carboxyl group reacts with an epoxy group to form an ester bond; a thiol group (—SH) reacts with an isocyanate to form a thiocarbamate linkage (—N—C(O)—S—); a thiol group reacts with an epoxy or aziridine to form a thioether linkage (—S—); a thiol group reacts with an acid chloride or bromide group or with an acid anhydride group to form a thiolester linkage; a thiol group reacts with an azlactone group in the presence of a catalyst to form a linkage (—C(O)NH—CR₃R₄—(CH₂)p-C(O)—S—). A thiol group reacts with a vinyl group based on thiol-ene reaction under thiol-ene reaction conditions to form a thioether linkage (—S—). A thiol group reacts with an acryloyl or methacryloyl group based on Michael Addition under appropriate reaction conditions to form a thioether linkage.

It is also understood that coupling agents with two reactive functional groups may be used in the coupling reactions. A coupling agent having two reactive functional groups can be a diisocyanate, a di-acid halide, a di-carboxylic acid compound, a di-acid halide compound, a di-azlactone compound, a di-epoxy compound, a diamine, or a diol. A person skilled in the art knows well to select a coupling reaction (e.g., anyone described above in this application) and conditions thereof to prepare a polysiloxane terminated with one or more ethylenically unsaturated groups. For example, a diisocyanate, di-acid halide, di-carboxylic acid, di-azlactone, or di-epoxy compound can be used in the coupling of two hydroxyl, two amino groups, two carboxyl groups, two epoxy groups, or combination thereof; a diamine or dihydroxyl compound can be used in the coupling of two isocyanate, epoxy, aziridine, carboxylic acid, acid halide or azlactone groups or combinations thereof.

Any suitable C₄-C₂₄ diisocyanates can be used in the invention. Examples of preferred diisocyanates include without limitation isophorone diisocyanate, hexamethyl-1,6-diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, toluene diisocyanate, 4,4′-diphenyl diisocyanate, 4,4′-diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,4-phenylene 4,4′-diphenyl diisocyanate, 1,3-bis-(4,4′-isocyanto methyl)cyclohexane, cyclohexane diisocyanate, and combinations thereof.

Any suitable diamines can be used in the invention. An organic diamine can be a linear or branched C₂-C₂₄ aliphatic diamine, a C₅-C₂₄ cycloaliphatic or aliphatic-cycloaliphatic diamine, or a C₆-C₂₄ aromatic or alkyl-aromatic diamine. A preferred organic diamine is N,N′-bis(hydroxyethyl)ethylenediamine, N,N′-dimethylethylenediamine, ethylenediamine, N,N′-dimethyl-1,3-propanediamine, N,N′-diethyl-1,3-propanediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, and isophorone diamine.

Any suitable diacid halides can be used in the invention. Examples of preferred diacid halide include without limitations fumaryl chloride, suberoyl chloride, succinyl chloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, sebacoyl chloride, adipoyl chloride, trimethyladipoyl chloride, azelaoyl chloride, dodecanedioic acid chloride, succinic chloride, glutaric chloride, oxalyl chloride, dimer acid chloride, and combinations thereof.

Any suitable di-epoxy compounds can be used in the invention. Examples of preferred di-epoxy compounds are neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, and combinations thereof. Such di-epoxy compounds are available commercially (e.g., those DENACOL series di-epoxy compounds from Nagase ChemteX Corporation).

Any suitable C₂-C₂₄ diols (i.e., compounds with two hydroxyl groups) can be used in the invention. Examples of preferred diols include without limitation ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, 1,4-butanediol, various pentanediols, various hexanediols, various cyclohexanediols, and combination thereof.

Any suitable C₃-C₂₄ di-carboxylic acid compounds can be used in the invention. Examples of preferred di-carboxylic acid compounds include without limitation a linear or branched C₃-C₂₄ aliphatic dicarboxylic acid, a C₅-C₂₄ cycloaliphatic or aliphatic-cycloaliphatic dicarboxylic acid, a C₆-C₂₄ aromatic or araliphatic dicarboxylic acid, a dicarboxylic acid which contains amino or imido groups or N-heterocyclic rings, and combinations thereof. Examples of suitable aliphatic dicarboxylic acids are: oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, dimethylmalonic acid, octadecylsuccinic acid, trimethyladipic acid, and dimeric acids (dimerisation products of unsaturated aliphatic carboxylic acids, such as oleic acid). Examples of suitable cycloaliphatic dicarboxylic acids are: 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3- and 1,4-cyclohexanedicarboxylic acid, 1,3- and 1,4-dicarboxylmethylcyclohexane, 4,4′-dicyclohexyldicarboxylic acid. Examples of suitable aromatic dicarboxylic acids are: terephthalic acid, isophthalic acid, o-phthalic acid, 1,3-, 1,4-, 2,6- or 2,7-naphthalenedicarboxylic acids, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenylsulphone-dicarboxylic acid, 1,1,3-trimethyl-5-carboxyl-3-(p-carboxyphenyl)-indane, 4,4′-diphenyl ether-dicarboxylic acid, bis-p-(carboxylphenyl)-methane.

Any suitable C₁₀-C₂₄ di-azlactone compounds can be used in the invention. Examples of such diazlactone compounds are those described in U.S. Pat. No. 4,485,236 (herein incorporated by reference in its entirety).

The reactions conditions for the above described coupling reactions are taught in textbooks and are well known to a person skilled in the art.

The term “ethylenically functionize” or ethylenically functionalization” in reference to a compound or polymer or copolymer having one or more reactive functional groups (e.g., amine, hydroxyl, carboxyl, isocyanate, anhydride, and/or epoxy groups) means a process or product thereof in which one or more ethylenically unsaturated groups are covalently attached to the functional groups of the compound or polymer or copolymer by reacting an ethylenically functionalizing vinylic monomer with the compound or polymer or copolymer under coupling reaction conditions.

An “ethylenically functionalizing vinylic monomer” throughout of this patent application refers to a vinylic monomer having one reactive functional group capable of participating in a coupling (or crosslinking) reaction known to a person skilled in the art. Examples of ethylenically-functionalizing vinylic monomers include without limitation C₂ to C₆ hydroxylalkyl(meth)acrylate, C₂ to C₆ hydroxyalkyl(meth)acrylamide, allylalcohol, allylamine, amino-C₂-C₆ alkyl(meth)acrylate, C₁-C₆ alkylamino-C₂-C₆ alkyl(meth)acrylate, vinylamine, amino-C₂-C₆ alkyl(meth)acrylamide, C₁-C₆ alkylamino-C₂-C₆ alkyl(meth)acrylamide, acrylic acid, C₁-C₄ alkylacrylic acid (e.g., methacrylic ethylacrylic acid, propylacrylic acid, butylacrylic acid), N-[tris(hydroxymethyl)-methyl]acrylamide, N,N-2-acrylamidoglycolic acid, beta methyl-acrylic acid (crotonic acid), alpha-phenyl acrylic acid, beta-acryloxy propionic acid, sorbic acid, angelic acid, cinnamic acid, 1-carobxy-4-phenyl butadiene-1,3, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, aziridinyl C₁-C₁₂ alkyl(meth)acrylate (e.g., 2-(1-aziridinyl)ethyl(meth)acrylate, 3-(1-aziridinyl)propyl(meth)acrylate, 4-(1-aziridinyl) butyl(meth)acrylate, 6-(1-aziridinyl)hexyl(meth)acrylate, or 8-(1-aziridinyl)octyl(meth)acrylate), glycidyl(meth)acrylate, vinyl glycidyl ether, allyl glycidyl ether, (meth)acryloyl halide groups (CH₂═CHCOX or CH₂═CCH₃—COX, X=Cl or Br), N-hydroxysuccinimide ester of (meth)acrylic acid, C₁ to C₆ isocyanatoalkyl(meth)acrylate, azlactone-containing vinylic monomers (e.g., 2-vinyl-4,4-dimethyl-1,3-oxazolin-5-one, 2-isopropenyl-4,4-dimethyl-1,3-oxazolin-5-one, 2-vinyl-4-methyl-4-ethyl-1,3-oxazolin-5-one, 2-isopropenyl-4-methyl-4-butyl-1,3-oxazolin-5-one, 2-vinyl-4,4-dibutyl-1,3-oxazolin-5-one, 2-isopropenyl-4-methyl-4-dodecyl-1,3-oxazolin-5-one, 2-isopropenyl-4,4-diphenyl-1,3-oxazolin-5-one, 2-isopropenyl-4,4-pentamethylene-1,3-oxazolin-5-one, 2-isopropenyl-4,4-tetramethylene-1,3-oxazolin-5-one, 2-vinyl-4,4-diethyl-1,3-oxazolin-5-one, 2-vinyl-4-methyl-4-nonyl-1,3-oxazolin-5-one, 2-isopropenyl-4-methyl-4-phenyl-1,3-oxazolin-5-one, 2-isopropenyl-4-methyl-4-benzyl-1,3-oxazolin-5-one, 2-vinyl-4,4-pentamethylene-1,3-oxazolin-5-one, and 2-vinyl-4,4-dimethyl-1,3-oxazolin-6-one, with 2-vinyl-4,4-dimethyl-1,3-oxazolin-5-one (VDMO) and 2-isopropenyl-4,4-dimethyl-1,3-oxazolin-5-one (IPDMO) as preferred azlactone-containing vinylic monomers), and combinations thereof.

In general, the invention is directed to a class of amphiphilic siloxane-containing (meth)acrylamides and uses in preparing a polymer (preferably an actinically-crosslinkable prepolymer or silicone hydrogel material) and in producing a medical device (preferably an ophthalmic devices, more preferably a silicone hydrogel contact lens). An amphiphilic siloxane-containing (meth)acrylamide of the invention comprises: one sole (meth)acrylamido group (preferably acrylamido group); one sole TRIS group; and one hydrophilic polyethylene glycol segment which is either a dangling polymer chain or a hydrophilic linker between the (meth)acrylamido group and the TRIS group. It is believed that an amphiphilic TRIS-containing (meth)acrylamide of the invention has an adequate solubility in water largely because of its hydrophilic polyethylene glycol segment present in the monomer. It can be used in a manufacturing process for making silicone hydrogel contact lenses in a more environmentally-friendly manner (e.g., using a water-based lens formulation and/or lens extraction with water). Further, a (meth)acrylamido group is less susceptible to hydrolysis than a (meth)acryloyloxy group while is more hydrophilic than a (meth)acryloyloxy group. In addition, because a (meth)acrylamide has a higher reactivity than a (meth)acrylate, a Tris-containing (meth)acrylamide of the invention is more suitable for a UV-polymerization process requiring a short curing time (e.g., within a time period of about 50 seconds or less).

The present invention, in one aspect, provides an amphiphilic siloxane-containing (meth)acrylamide being represented by formula (1) or (2)

in which

-   -   A₁, A₂, A₃ and A₄ independent of one another are a C₁-C₆ alkyl         (preferably methyl), phenyl or benzyl,     -   r1 is an integer of 2 or 3,     -   R′ is H or C₁-C₄ alkyl,     -   R₁₀ is hydrogen or methyl,     -   R₁₁ is a linear or branched C₂-C₆ alkylene divalent radical         which may be substituted with one or more hydroxyl groups,     -   R₁₂ is C₁-C₄ alkoxy,     -   Z₁ and Z₂ independent of each another are a direct bond or a         linear or branched C₁-C₄ alkylene divalent radical,     -   Z₃ is C₂-C₄ alkylene divalent radical,     -   Z₄, Z₅, and Z₆ independent of one another are a direct bond or a         linear or branched C₁-C₂₀ alkylene divalent radical which may         have one or more ether, thio, amine, carbonyl, or amido linkages         in their main chain,     -   X₁ is —O—CO—NH— or —O—CO—NH—R₁₃—NH—CO—O— in which R₁₃ is a         linear or branched C₂-C₁₂ alkylene divalent radical or a C₅-C₄₅         cycloaliphatic or aliphatic-cycloaliphatic divalent radical,     -   X₂ and X₃ independent of each other are selected from the group         consisting of direct bond, —O—, —NR′—, —CO—NR′—, —NR′—CO—,         —O—CO—NH—, —NH—CO—O—, —NR′—CO—NH—, —NH—CO—NR′—, —S—CO—NH—,         —NH—CO—S—, —S—, —CO—O—, —O—CO—, —O—CO—NH—R₁₃—NH—CO—O—, and         —NH—CO—NH—R₁₃—NH—CO—NH—, in which R′ and R₁₃ are as defined         above, q1 is an integer from 2 to 50, q2 is an integer from 3 to         20.

In a preferred embodiment, an amphiphilic siloxane-containing (meth)acrylamide of the invention is represented by formula (1) in which: R′ is hydrogen; R₁₀ is hydrogen or methyl; R₁₁ is a linear or branched C₂-C₆ alkylene divalent radical; R₁₂ is C₁-C₆ alkoxy; Z₁ and Z₂ are a direct bond; Z₃ is C₂-C₄ alkylene divalent radical; X₁ is —O—CO—NH— or —O—CO—NH—R₁₃—NH—CO—O— in which R₁₃ is a linear or branched C₂-C₁₂ alkylene divalent radical or a C₅-C₄₅ cycloaliphatic or aliphatic-cycloaliphatic divalent radical; q1 is an integer from 2 to 50.

In a preferred embodiment, an amphiphilic siloxane-containing (meth)acrylamide of the invention is represented by any one of formula (2a) to (2d)

in which: R₁₀ is hydrogen or methyl; R₁₁ is a linear or branched C₂-C₆ alkylene divalent radical; R₁₄ is —CH₂CH₂CH₂— or —CH₂CH(CH₃)—; X₄ and X₆ independent of each other are —O—, —NH—, —CO—NH—, —NH—CO—, —O—CO—NH—, —NH—CO—NH—, —CO—O—, —O—CO—, —S—, —O—CO—NH—R₁₃—NH—CO—O—, or —NH—CO—NH—R₁₃—NH—CO—NH— in which R₁₃ is a linear or branched C₂-C₁₂ alkylene divalent radical or a C₅-C₄₅ cycloaliphatic or aliphatic-cycloaliphatic divalent radical; X₅ is —NH—, —CO—NH—, —NH—CO—, —NH—CO—NH—, —CO—O—, —O—CO—, —S—, or —NH—CO—NH—R₁₃—NH—CO—NH— in which R₁₃ is a linear or branched C₂-C₁₂ alkylene divalent radical or a C₅-C₄₅ cycloaliphatic or aliphatic-cycloaliphatic divalent radical; q2 is an integer from 2 to 50; n1 and n3 independent of each other are an integer from 1 to 3; n2 is an integer 2 or 3.

An amphiphilic siloxane-containing (meth)acrylamide of formula (1) can be prepared from the following starting materials: (1) a (meth)acrylamide having one carboxyl (—COOH) group and one hydroxy (—OH) group (e.g., (meth)acrylamido glycolic acid or the like); (2) an isocyanatoalkly- or hydroxyalkyl-tris(trimethylsiloxy)silane or an isocyanato- or hydroxy-containing bulky silane (e.g., OCN—R₁₁-TRIS, HO—R₁₁-TRIS, OCN—R₁₁—Si(B₁)_(r1)(A₁)_(3-r1), HO—R₁₁—Si(B₁)_(r1)(A₁)_(3-r1) in which A₁, B₁ and r1 are as defined above, or the like); (3) mono-amine or mono-carboxy terminated polyethylene glycol (i.e., NH₂-PEG-OR₁₂ or HOOC-PEG-OR₁₂) according to coupling methods known to a person skilled in the art. As an illustrative example, Scheme I shows an illustrative scheme for preparing an amphiphilic siloxane-containing (meth)acrylamide of formula (1).

It should be understood that HOOC-PEG-OR₁₂ can substitute NH₂-PEG-OR₁₂ at step II and reacts with (meth)acrylamido glycolic acid N-hydroxysuccinimide ester in the presence of a diamine coupling agent (any one of those described above) to form a diamide linkage (instead of one sole amide linkage as shown in Scheme I). Similarly, OCN—R₁₁—Si(B₁)_(r1)(A₁)_(3-r1) can substitute OCN—R₁₁-TRIS at step III and reacts with the reaction product of step II; and HO—R₁₁-TRIS or HO—R₁₁—Si(B₁)_(r1)(A₁)_(3-r1) can substitute OCN—R₁₁-TRIS at step III and reacts with the reaction product of step II in the presence of a diisocyanate coupling agent (any one of those described above) to form a diurethane linkage (instead of one sole urethane linkage as shown in Scheme I).

Alternatively, an amphiphilic siloxane-containing (meth)acrylamide of formula (1) can be prepared from the following starting materials: (1) a compound having one amino group (—NHR′ with R′ as defined above), one carboxyl group and one hydroxy group (e.g., serine, threonine, L-β-Homoserine, L-β-homothreonine, L-β-Homohydroxyproline, or the like); (2) (meth)acrylic acid N-hydroxysuccinimide ester (commercially available from Sigma-Aldrich); (3) an isocyanatoalkly- or bromo- or chloro-alkyl- or hydroxyalkyl-tris(trimethylsiloxy)silane or an isocyanatoalkly- or bromo- or chloro-alkyl- or hydroxyalkyl-containing bulky silane; (4) mono-functional polyethylene glycol according to coupling methods known to a person skilled in the art. As an illustrative example, Scheme II shows another illustrative scheme for preparing an amphiphilic siloxane-containing (meth)acrylamide of formula (1) from serine.

It is understood that serine can be replaced by threonine, L-β-Homoserine, L-β-homothreonine, L-β-Homohydroxyproline in Scheme II for preparing an amphiphilic siloxane-containing (meth)acrylamide of formula (1). HOOC-PEG-OR₁₂ can substitute NH₂-PEG-OR₁₂ at step III and reacts with the reaction product of step II in the presence of a diamine coupling agent (any one of those described above) to form a diamide linkage (instead of one sole amide linkage as shown in Scheme II). Similarly, OCN—R₁₁—Si(B₁)_(r1)(A₁)_(3-r1) can substitute OCN—R₁₁-TRIS at step IV and reacts with the reaction product of step III; and HO—R₁₁-TRIS or HO—R₁₁—Si(B₁)_(r1)(A₁)_(3-r1) can substitute OCN—R₁₁-TRIS at step IV and reacts with the reaction product of step III in the presence of a diisocyanate coupling agent (any one of those described above) to form a diurethane linkage (instead of one sole urethane linkage as shown in Scheme II).

An amphiphilic siloxane-containing (meth)acrylamide of formula (2) can be prepared from the following starting materials: (1) an amino-containing or carboxy-containing (meth)acrylamide (e.g., N-(2-aminoethyl)methacrylamide hydrochloride, N-(3-aminopropyl)methacrylamide hydrochloride, N-(2-carboxypropyl)methacrylamide (2-CPMA), N-(3-carboxypropyl)methacrylamide (3-CPMA), N,N-2-acrylamidoglycolic acid, or the like); (2) a heterobifunctional polyethylene glycol (e.g., HO-PEG-COOH, HO-PEG-NH₂, NH₂-PEG-COOH, HS-PEG-COOH, HS-PEG-NH₂, Boc-NH-PEG-NHS, Boc-NH-PEG-NH₂, Boc-NH-PEG-NHS, in which Boc stands for amino protecting group—tert-Butyl carbamate, all of which are available from Creative PEGWORKs); (3) a tris(trimethylsiloxy)silane having a reactive functional group selected from the group consisting of amino, carboxy, isocyanato, and hydroxy group (e.g., aminopropyl-tris(trimethylsiloxy)silane, isocyanatopropyl-tris(trimethylsiloxy)silane, hydroxyethoxypropyl-tris(trimethylsiloxy)silane, chloropropyl-tris(trimethylsiloxy)silane, the Michael reaction product of carboxy-containing mercaptane (e.g., 2-mercaptopropinic acid, thioglycolic acid, thiolactic acid, or the like) with vinyl tris(trimethylsiloxy)silane).

As an illustrative example, Scheme III shows an illustrative scheme for preparing an amphiphilic siloxane-containing (meth)acrylamide of formula (2a).

It is understood that NH₂-PEG-COOH can be replaced by NH₂-PEG-OH or NH₂-PEG-SH or NH₂-PEG-NH-Boc in Scheme III step I to obtain a (meth)acrylamido-terminated, hydroxy-terminated (or HS-terminated or Boc-terminated polyethylene glycol). Where the functional group of the reaction product of step I in Scheme III is hydroxy group, it can react with an isocyanatoalkyl tris(trimethylsiloxy)silane to form a (meth)acrylamide of formula (2a), or alternatively it can reacts with hydroxyethoxypropyl tris(trimethylsiloxy)silane in the presence of a diisocyanate coupling agent (any one of those described above) under coupling reaction conditions (Tin catalyst, heating). Where the functional group of the reaction product of step I in Scheme III is Boc, Boc can be removed to recover NH₂ group which then can react with an isocyanatoalkyl tris(trimethylsiloxy)silane, with a carboxy-containing tris(trimethylsiloxy)silane in the presence of EDC and hydroxysuccinimide (HO—NHS), or with aminoalkyl-tris(trimethylsiloxy)silane in the presence of a diacid coupling agent (anyone of those described above) or a diacid chloride (anyone of those described above) or a diisocyanate coupling agent (any one of those described above) under coupling reaction conditions (Tin catalyst, heating), to form a (meth)acrylamide of formula (2a). Where the functional group of the reaction product of step I in Scheme III is thiol group, it can react with an isocyanatoalkyl tris(trimethylsiloxy)silane or with a vinyl tris(trimethylsiloxy)silane under Michael Addition reaction conditions, to form a (meth)acrylamide of formula (2a).

Scheme IV illustrate a scheme for preparing an amphiphilic siloxane-containing (meth)acrylamide of formula (2b).

It is understood that NH₂-PEG-COOH can be replaced by NH₂-PEG-NH-Boc or NH₂-PEG-SH in Scheme IV step I to obtain a (meth)acrylamido-terminated, Boc-terminated (or HS-terminated) polyethylene glycol. Where the functional group of the reaction product of step I in Scheme IV is Boc, Boc can be removed to recover NH₂ group which then can react with an isocyanatoalkyl tris(trimethylsiloxy)silane or with a carboxy-containing tris(trimethylsiloxy)silane in the presence of EDC and hydroxysuccinimide (HO—NHS), or with aminoalkyl-tris(trimethylsiloxy)silane in the presence of a diacid coupling agent (anyone of those described above) or a diisocyanate coupling agent (any one of those described above) under coupling reaction conditions, to form a (meth)acrylamide of formula (2b). Where the functional group of the reaction product of step I in Scheme IV is thiol group, it can react with an isocyanatoalkyl tris(trimethylsiloxy)silane or with a vinyl tris(trimethylsiloxy)silane under Michael Addition reaction conditions, to form a (meth)acrylamide of formula (2b).

Scheme V illustrates a scheme for preparing an amphiphilic siloxane-containing (meth)acrylamide of formula (2c).

It is understood that HO-PEG-NHS can be replaced by NHS-PEG-NH-Boc or NHS-PEG-SH in Scheme V step I to obtain a (meth)acrylamido-terminated, Boc-terminated (or HS-terminated) polyethylene glycol. Where the functional group of the reaction product of step I in Scheme V is Boc, Boc can be removed by well-known hydrolysis to recover NH₂ group which then can react with an isocyanatoalkyl tris(trimethylsiloxy)silane or with a carboxy-containing tris(trimethylsiloxy)silane in the presence of EDC and N-hydroxysuccinimide (HO—NHS), or with aminoalkyl-tris(trimethylsiloxy)silane in the presence of a diacid coupling agent (anyone of those described above) or a diisocyanate coupling agent (any one of those described above) under coupling reaction conditions, to form a (meth)acrylamide of formula (2c). Where the functional group of the reaction product of step I in Scheme V is thiol group, it can react with an isocyanatoalkyl tris(trimethylsiloxy)silane or with a vinyl tris(trimethylsiloxy)silane under Michael Addition reaction conditions, to form a (meth)acrylamide of formula (2c).

An amphiphilic siloxane-containing (meth)acrylamide of formula (2d) can be prepared according to Scheme IV from any carboxy-containing (meth)acrylamide (e.g., N-(2-carboxypropyl)methacrylamide (2-CPMA), N-(3-carboxypropyl)methacrylamide (3-CPMA)) which replaces (meth)acrylamido glycolic acid in Scheme IV.

In a preferred embodiment, an amphiphilic siloxane-containing (meth)acrylamide of any one of formula (1), (2), and (2a) to (2d) has a water solubility or dispersibility of at least about 5%, preferably at least about 10%, more preferably at least about 20% by weight in water.

An amphiphilic siloxane-containing (meth)acrylamide of formula (1) or (2) (including those preferred embodiments described above) as defined above can find particular use in preparing a polymer, preferably a silicone-containing actinically-crosslinkable prepolymer or a silicone hydrogel polymeric material, which is another aspect of the invention. A person skilled in the art knows how to prepare a polymer, an actinically-crosslinkable silicone containing prepolymer, or a silicone hydrogel polymeric material from a polymerizable composition according to any known polymerization mechanism.

In this aspect of the invention, a polymer can be a copolymer soluble or insoluble in a solvent, preferably an actinically-crosslinkable prepolymer or a silicone hydrogel material.

Various embodiments of amphiphilic siloxane containing vinylic monomers of formula (I) can be used in a polymerizable composition for preparing a polymer, a prepolymer or a silicone hydrogel material of the invention. It is understood that a polymerizable composition for preparing a polymer, an actinically-crosslinkable silicone-containing prepolymer or a silicone hydrogel polymeric material of the invention may optionally comprise a hydrophilized siloxane-containing (meth)acrylamide having at least one hydrophilic moiety selected from the group consisting of a short hydrophilic polymeric chain with a molecular weight of up to about 1000 Daltons (preferably about 800 Dalton or less, even more preferably about 500 Daltons or less), a pendant hydroxyl group, an amide linkage, a urethane linkage (or carbamate linkage), a diurethane linkage, a 2-hydroxy-substituted propyleneoxide linkage, and combinations thereof. Examples of hydrophilized siloxane-containing vinylic monomers include without limitation those described in U.S. Pat. No. 4,711,943, 5,070,215, 5,760,100 (Macromer C), U.S. Pat. No. 5,981,615, 5,998,498, 7,071,274, 7,112,641, 8,071,703, 8,044,111, and 8,048,968; in PCT patent application publication WO0059970; and in US patent application Nos. 2010/0120939 A1, 2010/0298446 A1, 2012/0088843 A1, 2012/0088844 A1, and 2012/0088861 A1, all of which are herein incorporated by reference in their entireties.

A person skilled in the art knows how to prepare a polymer, an actinically-crosslinkable silicone-containing prepolymer, or a silicone hydrogel material from a polymerizable composition according to any known free-radical polymerization mechanism. The polymerizable composition for preparing a polymer, an intermediary copolymer for preparing an actinically-crosslinkable silicone containing prepolymer, or a silicone hydrogel polymeric material of the invention can be a melt, a solventless liquid in which all necessary components are blended together, or a solution in which all necessary component is dissolved in an inert solvent, such as water, an organic solvent, or mixture thereof, as known to a person skilled in the art.

Example of suitable solvents includes without limitation, water, tetrahydrofuran, tripropylene glycol methyl ether, dipropylene glycol methyl ether, ethylene glycol n-butyl ether, ketones (e.g., acetone, methyl ethyl ketone, etc.), diethylene glycol n-butyl ether, diethylene glycol methyl ether, ethylene glycol phenyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-butyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether dipropylene glycol dimethyl ether, polyethylene glycols, polypropylene glycols, ethyl acetate, butyl acetate, amyl acetate, methyl lactate, ethyl lactate, i-propyl lactate, methylene chloride, 2-butanol, 1-propanol, 2-propanol, menthol, cyclohexanol, cyclopentanol and exonorborneol, 2-pentanol, 3-pentanol, 2-hexanol, 3-hexanol, 3-methyl-2-butanol, 2-heptanol, 2-octanol, 2-nonanol, 2-decanol, 3-octanol, norborneol, tert-butanol, tert-amyl, alcohol, 2-methyl-2-pentanol, 2,3-dimethyl-2-butanol, 3-methyl-3-pentanol, 1-methylcyclohexanol, 2-methyl-2-hexanol, 3,7-dimethyl-3-octanol, 1-chloro-2-methyl-2-propanol, 2-methyl-2-heptanol, 2-methyl-2-octanol, 2,2-methyl-2-nonanol, 2-methyl-2-decanol, 3-methyl-3-hexanol, 3-methyl-3-heptanol, 4-methyl-4-heptanol, 3-methyl-3-octanol, 4-methyl-4-octanol, 3-methyl-3-nonanol, 4-methyl-4-nonanol, 3-methyl-3-octanol, 3-ethyl-3-hexanol, 3-methyl-3-heptanol, 4-ethyl-4-heptanol, 4-propyl-4-heptanol, 4-isopropyl-4-heptanol, 2,4-dimethyl-2-pentanol, 1-methylcyclopentanol, 1-ethylcyclopentanol, 1-ethylcyclopentanol, 3-hydroxy-3-methyl-1-butene, 4-hydroxy-4-methyl-1-cyclopentanol, 2-phenyl-2-propanol, 2-methoxy-2-methyl-2-propanol 2,3,4-trimethyl-3-pentanol, 3,7-dimethyl-3-octanol, 2-phenyl-2-butanol, 2-methyl-1-phenyl-2-propanol and 3-ethyl-3-pentanol, 1-ethoxy-2-propanol, 1-methyl-2-propanol, t-amyl alcohol, isopropanol, 1-methyl-2-pyrrolidone, N,N-dimethylpropionamide, dimethyl formamide, dimethyl acetamide, dimethyl propionamide, N-methylpyrrolidinone, and mixtures thereof.

The copolymerization of a polymerizable composition for preparing a polymer, an actinically-crosslinkable silicone containing prepolymer (i.e., an intermediary copolymer for the prepolymer), or a silicone hydrogel polymeric material of the invention may be induced photochemically or thermally.

Suitable photoinitiators are benzoin methyl ether, diethoxyacetophenone, a benzoylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone and Darocur and Irgacure types, preferably Darocur 1173®, Irgacure 369®, Irgacure 379®, and Irgacure 2959®. Examples of benzoylphosphine oxide initiators include 2,4,6-trimethylbenzoyldiphenylophosphine oxide (TPO); bis-(2,6-dichlorobenzoyl)-4-N-propylphenylphosphine oxide; and bis-(2,6-dichlorobenzoyl)-4-N-butylphenylphosphine oxide. Reactive photoinitiators which can be incorporated, for example, into a macromer or can be used as a special monomer are also suitable. Examples of reactive photoinitiators are those disclosed in EP 632 329, herein incorporated by reference in its entirety. The polymerization can then be triggered off by actinic radiation, for example light, in particular UV light of a suitable wavelength. The spectral requirements can be controlled accordingly, if appropriate, by addition of suitable photosensitizers.

Suitable thermal polymerization initiators are known to the skilled artisan and comprise, for example peroxides, hydroperoxides, azo-bis(alkyl- or cycloalkylnitriles), persulfates, percarbonates or mixtures thereof. Examples are benzoylperoxide, tert.-butyl peroxide, di-tert.-butyl-diperoxyphthalate, tert.-butyl hydroperoxide, azo-bis(isobutyronitrile) (AIBN), 1,1-azodiisobutyramidine, 1,1′-azo-bis(1-cyclohexanecarbonitrile), 2,2′-azo-bis(2,4-dimethyl-valeronitrile) and the like. The polymerization is carried out conveniently in an above-mentioned solvent at elevated temperature, for example at a temperature of from 25 to 100° C. and preferably 40 to 80° C. The reaction time may vary within wide limits, but is conveniently, for example, from 1 to 24 hours or preferably from 2 to 12 hours. It is advantageous to previously degas the components and solvents used in the polymerization reaction and to carry out said copolymerization reaction under an inert atmosphere, for example under a nitrogen or argon atmosphere.

Generally, a polymer of the invention is obtained by polymerizing thermally or actinically a polymerizable composition including an amphiphilic siloxane-containing (meth)acrylamide of formula (1) or (2) as defined above and one or more polymerizable components selected from the group consisting of a hydrophilic vinylic monomer, a hydrophobic vinylic monomer, a polysiloxane-containing vinylic monomer, a polysiloxane-containing crosslinker, a non-silicone crosslinker, a hydrophilic prepolymer, a UV-absorbing vinylic monomer, and combinations thereof. Various embodiments of all of the above-described polymerizable components are discussed below.

In accordance with the invention, any suitable hydrophilic vinylic monomers can be used in a polymerizable composition for preparing a polymer of the invention. Examples of preferred hydrophilic vinylic monomers include without limitation N-vinylpyrrolidone, N,N-dimethyl(meth)acrylamide, (meth)acrylamide, hydroxylethyl(meth)acrylamide, hydroxyethyl(meth)acrylate, glycerol methacrylate (GMA), polyethylene glycol (meth)acrylate, polyethylene glycol C₁-C₄-alkyl ether (meth)acrylate having a weight average molecular weight of up to 1500, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone, 1-ethyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 1-ethyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, 5-ethyl-3-methylene-2-pyrrolidone, (meth)acrylic acid, ethylacrylic acid, and combinations thereof.

Any suitable hydrophobic vinylic monomers can be used in a polymerizable composition for making a polymer of the invention. By incorporating a certain amount of hydrophobic vinylic monomer in a monomer mixture, the mechanical properties (e.g., modulus of elasticity) of the resultant polymer may be improved. Examples of preferred hydrophobic vinylic monomers include methylacrylate, ethyl-acrylate, propylacrylate, isopropylacrylate, cyclohexylacrylate, 2-ethylhexylacrylate, methylmethacrylate, ethylmethacrylate, propylmethacrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, styrene, chloroprene, vinyl chloride, vinylidene chloride, acrylonitrile, 1-butene, butadiene, methacrylonitrile, vinyl toluene, vinyl ethyl ether, perfluorohexylethyl-thio-carbonyl-aminoethyl-methacrylate, isobornyl methacrylate, trifluoroethyl methacrylate, hexafluoro-isopropyl methacrylate, hexafluorobutyl methacrylate.

Any suitable polysiloxane-containing (meth)acrylamide (each comprising at least one polysiloxane segment and one sole ethylenically unsaturated group) can be used in a polymerizable composition for preparing a polymer of the invention. Preferred examples of such vinylic monomers are mono-(meth)acrylated polydimethylsiloxanes of various molecular weight (e.g., mono-3-methacryloxypropyl terminated, mono-C₁-C₄ alkyl terminated polydimethylsiloxane, or mono-(3-methacryloxy-2-hydroxypropyloxy)propyl terminated, mono-C₁-C₄ alkyl terminated polydimethylsiloxane). Alternatively, monoethylenically functionalized polysiloxanes can be obtained by ethylenically functionalizing of a monofunctionalized polysiloxanes (i.e., with one sole terminal functional group, such as, e.g., —NH₂, —OH, —COOH, epoxy group, halide, etc.) as described above. Suitable monofunctionalized polysiloxanes are commercially available, e.g., from Aldrich, ABCR GmbH & Co., Fluorochem, or Gelest, Inc, Morrisville, Pa.

Any suitable polysiloxane-containing crosslinkers (each of which comprises at least one polysiloxane segment and at least two ethylenically unsaturated groups) can be used in a polymerizable composition for preparing a polymer of the invention. Examples of polysiloxane-containing crosslinkers include without limitation, bis-(meth)acrylated polydimethylsiloxanes; bis-vinyl carbonate-terminated polydimethylsiloxanes; bis-vinyl carbamate-terminated polydimethylsiloxane; bis-vinyl terminated polydimethylsiloxanes; bis-(meth)acrylamide-terminated polydimethylsiloxanes; bis-3-methacryloxy-2-hydroxypropyloxypropyl polydimethylsiloxane; N,N,N′,N′-tetrakis(3-methacryloxy-2-hydroxypropyl)-alpha,omega-bis-3-aminopropyl-polydimethylsiloxane; polysiloxane or chain-extended polysiloxane crosslinkers selected from the group consisting of Macromer A, Macromer B, Macromer C, and Macromer D described in U.S. Pat. No. 5,760,100 (herein incorporated by reference in its entirety); the reaction products of glycidyl(meth)acrylate with bis-aminoalkyl-terminated or bis-hydroxyalkoxyalkyl terminated polydimethylsiloxanes; the reaction products of hydroxy-containing or amino-containing vinylic monomer with bis-epoxyalkoxyalkyl-terminated polydimethylsiloxanes; polysiloxane-containing crosslinkers disclosed in U.S. Pat. Nos. 4,136,250, 4,153,641, 4,182,822, 4,189,546, 4,259,467, 4,260,725, 4,261,875, 4,343,927, 4,254,248, 4,355,147, 4,276,402, 4,327,203, 4,341,889, 4,486,577, 4,543,398, 4,605,712, 4,661,575, 4,684,538, 4,703,097, 4,833,218, 4,837,289, 4,954,586, 4,954,587, 5,010,141, 5,034,461, 5,070,170, 5,079,319, 5,039,761, 5,346,946, 5,358,995, 5,387,632, 5,416,132, 5,451,617, 5,486,579, 5,962,548, 5,981,675, 6,039,913, 6,762,264, 7,091,283, 7,238,750, 7,268,189, 7,566,754, 7,956,135, 8,071,696, 8,071,703, 8,071,658, 8,048,968, 8,283,429, 8,263,679, 8,044,111, and 8,211,955 and in published US patent application Nos. 2008/0015315 A1, 2010/0120939 A1, 2010/0298446 A1, 2010/0296049 A1, 2011/0063567 A1, 2012/0088843 A1, 2012/0088844 A1, 2012/0029111 A1, and 2012/0088861 A1 (herein incorporated by reference in their entireties). In a preferred embodiment, a polysiloxane-containing crosslinker used in a polymerizable composition for preparing a polymer, an anctinically-crosslinkable silicone containing prepolymer, or a silicone hydrogel polymeric material of the invention is hydrophilized, namely a crosslinker containing at least one polysiloxane segment and at least one pendant hydrophilic polymer chain. Examples of hydrophilized polysiloxane-containing crosslinkers include without limitation those described in US patent application Nos. 2010/0120939 A1, 2010/0298446 A1, 2012/0088843 A1, 2012/0088844 A1, and 2012/0088861 A1, all of which are herein incorporated by reference in their entireties.

Any suitable non-silicone crosslinkers can be used in a polymerizable composition for preparing a polymer of the invention. Examples of preferred non-silicone crosslinkers include without limitation tetraethyleneglycol di-(meth)acrylate, triethyleneglycol di-(meth)acrylate, ethyleneglycol di-(meth)acrylate, diethyleneglycol di-(meth)acrylate, bisphenol A dimethacrylate, vinyl methacrylate, ethylenediamine di(meth)acrylamide, glycerol dimethacrylate, allyl(meth)acrylate, N,N′-methylenebis(meth)acrylamide, N,N′-ethylenebis(meth)acrylamide, N,N′-dihydroxyethylene bis(meth)acrylamide, a product of diamine (preferably selected from the group consisting of N,N′-bis(hydroxyethyl)ethylenediamine, N,N′-dimethylethylenediamine, ethylenediamine, N,N′-dimethyl-1,3-propanediamine, N,N′-diethyl-1,3-propanediamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, isophorone diamine, and combinations thereof) and epoxy-containing vinylic monomer (preferably selected from the group consisting of glycidyl(meth)acrylate, vinyl glycidyl ether, allyl glycidyl ether, and combinations thereof), combinations thereof. A more preferred crosslinker to be used in the preparation of a polymer, an actinically-crosslinkable silicone containing prepolymer, or a silicone hydrogel polymeric material of the invention is a hydrophilic crosslinker selected from the group consisting of tetra(ethyleneglycol)diacrylate, tri(ethyleneglycol)diacrylate, ethyleneglycol diacrylate, di(ethyleneglycol)diacrylate, glycerol dimethacrylate, allyl(meth)acrylate, N,N′-methylene bis(meth)acrylamide, N,N′-ethylene bis(meth)acrylamide, N,N′-dihydroxyethylene bis(meth)acrylamide, and combinations thereof.

Examples of hydrophilic prepolymers with multiple acryloyl or methacryloyl groups include, but are not limited to, a water-soluble crosslinkable poly(vinyl alcohol) prepolymer described in U.S. Pat. Nos. 5,583,163 and 6,303,687; a water-soluble vinyl group-terminated polyurethane prepolymer described in U.S. Patent Application Publication No. 2004/0082680; derivatives of a polyvinyl alcohol, polyethyleneimine or polyvinylamine, which are disclosed in U.S. Pat. No. 5,849,841; a water-soluble crosslinkable polyurea prepolymer described in U.S. Pat. No. 6,479,587 and in U.S. Published Application No. 2005/0113549; crosslinkable polyacrylamide; crosslinkable statistical copolymers of vinyl lactam, MMA and a comonomer, which are disclosed in EP 655,470 and U.S. Pat. No. 5,712,356; crosslinkable copolymers of vinyl lactam, vinyl acetate and vinyl alcohol, which are disclosed in EP 712,867 and U.S. Pat. No. 5,665,840; polyether-polyester copolymers with crosslinkable side chains which are disclosed in EP 932,635 and U.S. Pat. No. 6,492,478; branched polyalkylene glycol-urethane prepolymers disclosed in EP 958,315 and U.S. Pat. No. 6,165,408; polyalkylene glycol-tetra(meth)acrylate prepolymers disclosed in EP 961,941 and U.S. Pat. No. 6,221,303; and crosslinkable polyallylamine gluconolactone prepolymers disclosed in International Application No. WO 2000/31150 and U.S. Pat. No. 6,472,489.

Any suitable UV-absorbing vinylic monomers can be used in a polymerizable composition for preparing a polymer of the invention. Preferred UV absorbing vinylic monomers include without limitation 2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, 2-(2-hydroxy-5-acrylyloxyphenyl)-2H-benzotriazole, 2-(2-hydroxy-3-methacrylamido methyl-5-tert octylphenyl)benzotriazole, 2-(2′-hydroxy-5′-methacrylamidophenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-5′-methacrylamidophenyl)-5-methoxybenzotriazole, 2-(2′-hydroxy-5′-methacryloxypropyl-3′-t-butyl-phenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-5′-methacryloxyethylphenyl)benzotriazole, 2-(2′-hydroxy-5′-methacryloxypropylphenyl)benzotriazole, 2-hydroxy-4-acryloxy alkoxy benzophenone, 2-hydroxy-4-methacryloxy alkoxy benzophenone, allyl-2-hydroxybenzophenone, 2-hydroxy-4-methacryloxy benzophenone. In accordance with the invention, the polymerizable composition comprises about 0.2% to about 5.0%, preferably about 0.3% to about 2.5%, more preferably about 0.5% to about 1.8%, by weight of a UV-absorbing vinylic monomer.

In a preferred embodiment, a polymer of the invention is a silicone-containing actinically-crosslinkable prepolymer, which preferably comprises: (1) monomeric units derived from an amphiphilic siloxane-containing (meth)acrylamide of any one of formula (1), (2), and (2a) to (2d) as defined above; (2) crosslinking units derived from at least one polysiloxane-containing crosslinker as described above (preferably a hydrophilized polysiloxane-containing crosslinker as described above) and/or polysiloxane units derived from a polysiloxane-containing vinylic monomer as described above; (3) hydrophilic units derived from at least one hydrophilic vinylic monomer as described above; (4) polymerizable units derived from a chain transfer agent having a first reactive functional group other than thiol group and/or a vinylic monomer having a second reactive functional group other than ethylenically-unsaturated group, wherein the polymerizable units each comprise an ethylenically unsaturated group covalently attached to one polymerizable unit through the first or second reactive functional group; (5) optionally non-silicone crosslinking units derived from at least one non-silicone crosslinker as described above (preferably a non-silicone, hydrophilic crosslinker as described above); and (6) optionally UV-absorbing units derived from a UV-absorbing vinylic monomer as described above. Such a prepolymer is capable of being actinically crosslinked, in the absence of one or more vinylic monomers, to form a silicone hydrogel contact lens having a water content of from about 20% to about 75% (preferably from about 25% to about 70%, more preferably from about 30% to about 65%) by weight when fully hydrated, and an oxygen permeability (Dk) of at least about 40 barrers (preferably at least about 50 barrers, more preferably at least about 60 barrers, and even more preferably at least about 70 barrers). Preferably, such a prepolymer is water soluble or processable. a non-silicone crosslinker as described above

Such a prepolymer is obtained by first polymerizing a polymerizable composition including all polymerizable components specified above, to form an intermediary copolymer and then by ethylenically functionalizing the intermediary copolymer with an ethylenically functionalizing vinylic monomer having a third reactive functional group capable of reacting with the first and/or second reactive functional group to form a linkage in a coupling reaction in the presence or absence of a coupling agent to form the prepolymer, wherein the first, second and third reactive functional groups independent of one another are selected from the group consisting of amino group, hydroxyl group, carboxyl group, acid halide group, azlactone group, isocyanate group, epoxy group, aziridine group, and combination thereof. The general procedures for preparing amphiphilic prepolymers are disclosed in U.S. Pat. Nos. 6,039,913, 6,043,328, 7,091,283, 7,268,189 and 7,238,750, 7,521,519, 8,071,703, 8,044,111, and 8,048,968; in US patent application publication Nos. US 2008-0015315 A1, US 2008-0143958 A1, US 2008-0143003 A1, US 2008-0234457 A1, US 2008-0231798 A1, 2010/0120939 A1, 2010/0298446 A1, 2012/0088843 A1, 2012/0088844 A1, and 2012/0088861 A1; all of which are incorporated herein by references in their entireties.

In accordance with the invention, the polymerizable units each comprise a basic monomeric unit being a part of a polymer chain of the prepolymer and a pendant or terminal, ethylenically-unsaturated group attached thereon, wherein each basic monomeric unit is derived from a first ethylenically functionalizing vinylic monomer having a second reactive functional group, wherein the pendant or terminal ethylenically unsaturated group is derived from a second ethylenically functionalizing vinylic monomer having a third reactive functional group which reacts with one second reactive functional in the presence or absence of a crosslinking agent to form a covalent linkage. The second and third reactive functional groups are selected from the group consisting of amino group, hydroxyl group, carboxyl group, azlactone group, isocyanate group, epoxy group, aziridine group, acid chloride, and combination thereof. Examples of such vinylic monomers are those ethylenically functionalizing vinylic monomers described above. Preferably, the first ethylenically functionalizing vinylic monomer is selected from the group consisting of hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxyethyl(meth)acrylamide, hydroxypropyl(meth)acrylamide, allyl alcohol, aminoethyl(meth)acrylate, aminopropyl(meth)acrylate, aminoethyl(meth)acrylamide, aminopropyl(meth)acrylamide, allyl amine, (meth)acrylic acid, ethylacrylic acid, propylacrylic acid, butylacrylic acid, glycidyl(meth)acrylate, vinyl glycidyl ether, allyl glycidyl ether, isocynatoethyl(meth)acrylate, 2-(1-aziridinyl)ethyl(meth)acrylate, 3-(1-aziridinyl) propyl(meth)acrylate, 4-(1-aziridinyl) butyl(meth)acrylate, 2-vinyl-4,4-dimethyl-1,3-oxazolin-5-one (VDMO), 2-isopropenyl-4,4-dimethyl-1,3-oxazolin-5-one (IPDMO), and combination thereof. Most preferably, the first ethylenically functionalizing vinylic monomer is selected from the group consisting of hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxyethyl(meth)acrylamide, hydroxypropyl(meth)acrylamide, allyl alcohol, aminoethyl(meth)acrylate, aminopropyl(meth)acrylate, aminoethyl(meth)acrylamide, aminopropyl(meth)acrylamide, allyl amine, and combinations thereof.

In accordance with the invention, the content of the polymerizable units are determined based on weight percentage of the ethylenically functionalizing vinylic monomer present in the polymerizable composition for making an water-processable intermediary copolymer relative to the total weight of polymerizable components in the polymerizable composition or the weight percentage of the ethylenically functionalizing vinylic monomer used in ethylenically functionalizing the intermediary copolymer to form the prepolymer of the invention, relative to the weight of the prepolymer.

A chain transfer agent (containing at least one thiol group) is used to control the molecular weight of the resultant intermediary copolymer. Where a chain transfer has a reactive functional group such as amine, hydroxyl, carboxyl, epoxy, isocyanate, azlactone, or aziridine group, it can provide terminal or pendant functionality (amine, hydroxyl, carboxyl, epoxy, isocyanate, azlactone, or aziridine group) for subsequent ethylenical functionalization of the resultant intermediary copolymer.

In a preferred embodiment, an actinically-crosslinkable silicone-containing prepolymer of the invention is a water-processable prepolymer that has a high water solubility or dispersibility of at least about 5%, preferably at least about 10%, more preferably at least about 20% by weight in water. The prepolymer is capable of being actinically crosslinked, in the absence of one or more vinylic monomers, to form a silicone hydrogel contact lens having a water content of from about 20% to about 75% (preferably from about 25% to about 70%, more preferably from about 30% to about 65%) by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers (preferably at least about 50 barrers, more preferably at least about 60 barrers, and even more preferably at least about 70 barrers). A water-processable prepolymer of the invention can find particular use in preparing silicone hydrogel ophthalmic lenses, in particular contact lenses.

In another aspect, the invention provides a soft contact lens. The soft contact lens of the invention comprises: a silicone hydrogel material that is obtained by curing a lens-forming material in a mold, wherein the lens-forming formulation (or material) comprises at least one amphiphilic siloxane-containing (meth)acrylamide of the invention (as described above in detail) and/or at least one actinically-crosslinkable silicone-containing prepolymer of the invention (as described above in detail), wherein the contact lens has a water content of from about 20% to about 75% (preferably from about 25% to about 70%, more preferably from about 30% to about 65%) by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers (preferably at least about 50 barrers, more preferably at least about 60 barrers, and even more preferably at least about 70 barrers), and an elastic modulus of from about 0.1 MPa to about 2.0 MPa, preferably from about 0.2 MPa to about 1.5 MPa, more preferably from about 0.3 MPa to about 1.2 MPa, even more preferably from about 0.4 MPa to about 1.0 MPa. The lens-forming formulation for obtaining a soft contact lens of the invention can further comprise one or more components selected from the group consisting of a hydrophilic vinylic monomer, a polysiloxane-containing crosslinker, a non-silicone crosslinker, a photoinitiator, a thermal initiator, a UV-absorbing vinylic monomer, a visibility tinting agent (e.g., dyes, pigments, or mixtures thereof), antimicrobial agents (e.g., preferably silver nanoparticles), a bioactive agent, leachable lubricants, leachable tear-stabilizing agents, and mixtures thereof.

Various embodiments of amphiphili siloxane-containing vinylic monomers of formula (I), polysiloxane-containing crosslinkers, non-silicone crosslinkers, actinically-crosslinkable silicone containing prepolymers of the inventions, hydrophilic vinylic monomers, UV-absorbing vinylic monomers, solvents, photoinitiators, and thermal initiators are described above and can be used in this aspect of the invention.

The bioactive agent incorporated in the polymeric matrix is any compound that can prevent a malady in the eye or reduce the symptoms of an eye malady. The bioactive agent can be a drug, an amino acid (e.g., taurine, glycine, etc.), a polypeptide, a protein, a nucleic acid, or any combination thereof. Examples of drugs useful herein include, but are not limited to, rebamipide, ketotifen, olaptidine, cromoglycolate, cyclosporine, nedocromil, levocabastine, lodoxamide, ketotifen, or the pharmaceutically acceptable salt or ester thereof. Other examples of bioactive agents include 2-pyrrolidone-5-carboxylic acid (PCA), alpha hydroxyl acids (e.g., glycolic, lactic, malic, tartaric, mandelic and citric acids and salts thereof, etc.), linoleic and gamma linoleic acids, and vitamins (e.g., B5, A, B6, etc.).

Examples of leachable lubricants include without limitation mucin-like materials (e.g., polyglycolic acid) and non-crosllinkable hydrophilic polymers (i.e., without ethylenically unsaturated groups). Any hydrophilic polymers or copolymers without any ethylenically unsaturated groups can be used as leachable lubricants. Preferred examples of non-crosslinkable hydrophilic polymers include, but are not limited to, polyvinyl alcohols (PVAs), polyamides, polyimides, polylactone, a homopolymer of a vinyl lactam, a copolymer of at least one vinyl lactam in the presence or in the absence of one or more hydrophilic vinylic comonomers, a homopolymer of acrylamide or methacrylamide, a copolymer of acrylamide or methacrylamide with one or more hydrophilic vinylic monomers, polyethylene oxide (i.e., polyethylene glycol (PEG)), a polyoxyethylene derivative, poly-N—N-dimethylacrylamide, polyacrylic acid, poly 2 ethyl oxazoline, heparin polysaccharides, polysaccharides, and mixtures thereof. The weight-average molecular weight M_(w) of the non-crosslinkable hydrophilic polymer is preferably from 5,000 to 500,000, more preferably from 10,000 to 300,000, even more preferably from 20,000 to 100,000.

Examples of leachable tear-stabilizing agents include, without limitation, phospholipids, monoglycerides, diglycerides, triglycerides, glycolipids, glyceroglycolipids, sphingolipids, sphingo-glycolipids, fatty alcohols, fatty acids, mineral oils, and mixtures thereof. Preferably, a tear stabilizing agent is a phospholipid, a monoglyceride, a diglyceride, a triglyceride, a glycolipid, a glyceroglycolipid, a sphingolipid, a sphingo-glycolipid, a fatty acid having 8 to 36 carbon atoms, a fatty alcohol having 8 to 36 carbon atoms, or a mixture thereof.

In accordance with the invention, a lens-forming formulation (or material) is a fluid composition, which can be a solution or a melt at a temperature from about 20° C. to about 85° C. A lens forming formulation can be prepared by dissolving all of the desirable components in any suitable solvent known to a person skilled in the art, e.g., any one solvent described above. Preferably, a lens-forming material is a solution of all the desirable components in water, 1,2-propylene glycol, a polyethyleneglycol having a molecular weight of about 400 Daltons or less, or a mixture thereof.

Lens molds for making contact lenses are well known to a person skilled in the art and, for example, are employed in cast molding or spin casting. For example, a mold (for cast molding) generally comprises at least two mold sections (or portions) or mold halves, i.e. first and second mold halves. The first mold half defines a first molding (or optical) surface and the second mold half defines a second molding (or optical) surface. The first and second mold halves are configured to receive each other such that a lens forming cavity is formed between the first molding surface and the second molding surface. The molding surface of a mold half is the cavity-forming surface of the mold and in direct contact with lens-forming material.

Methods of manufacturing mold sections for cast-molding a contact lens are generally well known to those of ordinary skill in the art. The process of the present invention is not limited to any particular method of forming a mold. In fact, any method of forming a mold can be used in the present invention. The first and second mold halves can be formed through various techniques, such as injection molding or lathing. Examples of suitable processes for forming the mold halves are disclosed in U.S. Pat. No. 4,444,711 to Schad; U.S. Pat. No. 4,460,534 to Boehm et al.; U.S. Pat. No. 5,843,346 to Morrill; and U.S. Pat. No. 5,894,002 to Boneberqer et al., which are also incorporated herein by reference.

Virtually all materials known in the art for making molds can be used to make molds for making contact lenses. For example, polymeric materials, such as polyethylene, polypropylene, polystyrene, PMMA, Topas® COC grade 8007-S10 (clear amorphous copolymer of ethylene and norbornene, from Ticona GmbH of Frankfurt, Germany and Summit, N.J.), or the like can be used. Other materials that allow UV light transmission could be used, such as quartz glass and sapphire.

In accordance with the invention, the lens-forming formulation (or composition) can be introduced (dispensed) into a cavity formed by a mold according to any known methods.

After the lens-forming composition is dispensed into the mold, it is polymerized to produce a contact lens. Crosslinking may be initiated thermally or actinically, preferably by exposing the lens-forming composition in the mold to a spatial limitation of actinic radiation to crosslink the polymerizable components in the lens-forming composition.

Where the lens-forming composition comprises a UV-absorbing vinylic monomer, a benzoylphosphine oxide photoinitiator is preferably used as the photoinitiator in the invention. Preferred benzoylphosphine oxide photoinitiators include without limitation 2,4,6-trimethylbenzoyldiphenylophosphine oxide; bis-(2,6-dichlorobenzoyl)-4-N-propylphenylphosphine oxide; and bis-(2,6-dichlorobenzoyl)-4-N-butylphenylphosphine oxide. It is understood that any photoinitiators other than benzoylphosphine oxide initiators can be used in the invention.

Opening of the mold so that the molded article can be removed from the mold may take place in a manner known per se.

The molded contact lens can be subject to lens extraction to remove unpolymerized polymerizable components. The extraction solvent can be any solvent known to a person skilled in the art. Examples of suitable extraction solvent are those described above. Preferably, water or an aqueous solution is used as extraction solvent. After extraction, lenses can be hydrated in water or an aqueous solution of a wetting agent (e.g., a hydrophilic polymer).

The molded contact lenses can further subject to further processes, such as, for example, surface treatment, packaging in lens packages with a packaging solution which can contain about 0.005% to about 5% by weight of a wetting agent (e.g., a hydrophilic polymer described above or the like known to a person skilled in the art) and/or a viscosity-enhancing agent (e.g., methyl cellulose (MC), ethyl cellulose, hydroxymethylcellulose, hydroxyethyl cellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethyl cellulose (HPMC), or a mixture thereof); sterilization such as autoclave at from 118 to 1240° C. for at least about 30 minutes; and the like.

In a further aspect, the invention provides a method for making silicone hydrogel contact lenses. The method comprises the steps of: introducing a lens formulation into a mold for making contact lenses, wherein the lens-forming formulation comprises (a) a solvent selected from the group consisting of water, 1,2-propylene glycol, a polyethyleneglycol having a molecular weight of about 400 Daltons or less, and mixtures thereof, (b) at least one amphiphilic siloxane-containing (meth)acrylamide of formula (1) or (2) (as described above in detail) and/or at least one actinically-crosslinkable silicone containing prepolymer of the invention as described above in detail, and (c) at least one component selected from the group consisting of a hydrophilic vinylic monomer (as described above in detail), a hydrophilized polysiloxane-containing crosslinker (as described above in detail), a hydrophilic crosslinker (as described above in detail), a photoinitiator (as described above in detail), a thermal initiator (as described above in detail), a UV-absorbing vinylic monomer (as described above in detail), a visibility tinting agent (e.g., dyes, pigments, or mixtures thereof), antimicrobial agents (e.g., preferably silver nanoparticles), a bioactive agent (as described above in detail), leachable lubricants (as described above in detail), leachable tear-stabilizing agents (as described above in detail), and mixtures thereof; polymerizing the lens formulation in the mold to form a silicone hydrogel contact lens, wherein the formed silicone hydrogel contact lens has a water content of from about 20% to about 75% (preferably from about 25% to about 70%, more preferably from about 30% to about 65%) by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers (preferably at least about 50 barrers, more preferably at least about 60 barrers, and even more preferably at least about 70 barrers), and an elastic modulus of from about 0.1 MPa to about 2.0 MPa, preferably from about 0.2 MPa to about 1.5 MPa, more preferably from about 0.3 MPa to about 1.2 MPa, even more preferably from about 0.4 MPa to about 1.0 MPa.

Various embodiments of amphiphilic siloxane-containing vinylic monomers of formula (1) or (2), actinically-crosslinkable silicone containing prepolymers of the invention, lens forming formulations, hydrophilic vinylic monomers, hydrophilized polysiloxane-containing crosslinkers, hydrophilic crosslinkers, solvents, UV-absorbing vinylic monomers, photoinitiators, thermal initiators, visibility tinting agents, antimicrobial agents, bioactive agents, leachable lubricants, leachable tear-stabilizing agents, molds, polymerizing techniques, and post molding processes are described above and can be used in this aspect of the invention.

In a preferred embodiment, the resultant silicone hydrogel contact lens is extracted with water or an aqueous solution.

In another preferred embodiment, the mold is a reusable mold and the lens-forming composition is cured (i.e., polymerized) actinically under a spatial limitation of actinic radiation to form a silicone hydrogel contact lens. Examples of preferred reusable molds are those disclosed in U.S. Pat. Nos. 6,627,124, 6,800,225, 7,384,590, and 7,387,759, which are incorporated by reference in their entireties. Reusable molds can be made of quartz, glass, sapphire, CaF₂, a cyclic olefin copolymer (such as for example, Topas® COC grade 8007-S10 (clear amorphous copolymer of ethylene and norbornene) from Ticona GmbH of Frankfurt, Germany and Summit, N.J., Zeonex® and Zeonor® from Zeon Chemicals LP, Louisville, Ky.), polymethylmethacrylate (PMMA), polyoxymethylene from DuPont (Delrin), Ultem® (polyetherimide) from G.E. Plastics, PrimoSpire®, and combinations thereof.

Although various embodiments of the invention have been described using specific terms, devices, and methods, such description is for illustrative purposes only. The words used are words of description rather than of limitation. It is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit or scope of the present invention, which is set forth in the following claims. In addition, it should be understood that aspects of the various embodiments may be interchanged either in whole or in part or can be combined in any manner and/or used together. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained therein.

The previous disclosure will enable one having ordinary skill in the art to practice the invention. In order to better enable the reader to understand specific embodiments and the advantages thereof, reference to the following non-limiting examples is suggested. However, the following examples should not be read to limit the scope of the invention.

Example 1

The apparent oxygen permeability of a lens and oxygen transmissibility of a lens material is determined according to a technique similar to the one described in U.S. Pat. No. 5,760,100 and in an article by Winterton et al., (The Cornea: Transactions of the World Congress on the Cornea 111, H. D. Cavanagh Ed., Raven Press: New York 1988, pp 273-280), both of which are herein incorporated by reference in their entireties. Oxygen fluxes (J) are measured at 34° C. in a wet cell (i.e., gas streams are maintained at about 100% relative humidity) using a Dk1000 instrument (available from Applied Design and Development Co., Norcross, Ga.), or similar analytical instrument. An air stream, having a known percentage of oxygen (e.g., 21%), is passed across one side of the lens at a rate of about 10 to 20 cm³/min., while a nitrogen stream is passed on the opposite side of the lens at a rate of about 10 to 20 cm³/min. A sample is equilibrated in a test media (i.e., saline or distilled water) at the prescribed test temperature for at least 30 minutes prior to measurement but not more than 45 minutes. Any test media used as the overlayer is equilibrated at the prescribed test temperature for at least 30 minutes prior to measurement but not more than 45 minutes. The stir motor's speed is set to 1200±50 rpm, corresponding to an indicated setting of 400±15 on the stepper motor controller. The barometric pressure surrounding the system, P_(measured), is measured. The thickness (t) of the lens in the area being exposed for testing is determined by measuring about 10 locations with a Mitotoya micrometer VL-50, or similar instrument, and averaging the measurements. The oxygen concentration in the nitrogen stream (i.e., oxygen which diffuses through the lens) is measured using the DK1000 instrument. The apparent oxygen permeability of the lens material, Dk_(app), is determined from the following formula:

Dk _(app) =Jt/(P _(oxygen))

where J=oxygen flux [microliters O₂/cm²−minute]

P_(oxygen)=(P_(measured)−P_(water) vapor)=(% O₂ in air stream) [mm Hg]=partial pressure of oxygen in the air stream

P_(measured)=barometric pressure (mm Hg)

P_(water) vapor=0 mm Hg at 34° C. (in a dry cell) (mm Hg)

P_(water) vapor=40 mm Hg at 34° C. (in a wet cell) (mm Hg)

t=average thickness of the lens over the exposed test area (mm)

Dk_(app) is expressed in units of barrers.

The apparent oxygen transmissibility (Dk/t) of the material may be calculated by dividing the apparent oxygen permeability (Dk_(app)) by the average thickness (t) of the lens.

The above described measurements are not corrected for the so-called boundary layer effect which is attributable to the use of a water or saline bath on top of the contact lens during the oxygen flux measurement. The boundary layer effect causes the reported value for the apparent Dk of a silicone hydrogel material to be lower than the actual intrinsic Dk value. Further, the relative impact of the boundary layer effect is greater for thinner lenses than with thicker lenses. The net effect is that the reported Dk appear to change as a function of lens thickness when it should remain constant.

The intrinsic Dk value of a lens can be estimated based on a Dk value corrected for the surface resistance to oxygen flux caused by the boundary layer effect as follows.

Measure the apparent oxygen permeability values (single point) of the reference lotrafilcon A (Focus® N&D® from CIBA VISION CORPORATION) or lotrafilcon B (AirOptix™ from CIBA VISION CORPORATION) lenses using the same equipment. The reference lenses are of similar optical power as the test lenses and are measured concurrently with the test lenses.

Measure the oxygen flux through a thickness series of lotrafilcon A or lotrafilcon B (reference) lenses using the same equipment according to the procedure for apparent Dk measurements described above, to obtain the intrinsic Dk value (Dk_(i)) of the reference lens. A thickness series should cover a thickness range of approximately 100 μm or more. Preferably, the range of reference lens thicknesses will bracket the test lens thicknesses. The Dk_(app) of these reference lenses must be measured on the same equipment as the test lenses and should ideally be measured contemporaneously with the test lenses. The equipment setup and measurement parameters should be held constant throughout the experiment. The individual samples may be measured multiple times if desired.

Determine the residual oxygen resistance value, R_(r), from the reference lens results using equation 1 in the calculations.

$\begin{matrix} {R_{r} = \frac{\Sigma \left( {\frac{t}{{Dk}_{app}} - \frac{t}{{Dk}_{i}}} \right)}{n}} & (1) \end{matrix}$

in which t is the thickness of the test lens (i.e., the reference lens too), and n is the number of the reference lenses measured. Plot the residual oxygen resistance value, R_(r) vs. t data and fit a curve of the form Y=a+bX where, for the jth lens, Y_(j)=(ΔP/J)_(j) and X=t_(j). The residual oxygen resistance, R_(r) is equal to a.

Use the residual oxygen resistance value determined above to calculate the correct oxygen permeability Dk_(c) (estimated intrinsic Dk) for the test lenses based on Equation 2.

Dk _(c) =t/[(t/Dk _(a))−R _(r)]  (2)

The estimated intrinsic Dk of the test lens can be used to calculate what the apparent Dk (Dk_(a) _(—) _(std)) would have been for a standard thickness lens in the same test environment based on Equation 3. The standard thickness (t_(std)) for lotrafilcon A=85 μm. The standard thickness for lotrafilcon B=60 μm.

Dk _(a) _(—) _(std) =t _(std)/[(t _(std) /Dk _(c))+R _(r) _(—) _(std)]  (3)

Ion Permeability Measurements.

The ion permeability of a lens is measured according to procedures described in U.S. Pat. No. 5,760,100 (herein incorporated by reference in its entirety. The values of ion permeability reported in the following examples are relative ionoflux diffusion coefficients (D/D_(ref)) in reference to a lens material, Alsacon, as reference material. Alsacon has an ionoflux diffusion coefficient of 0.314×10⁻³ mm²/minute.

Folding Mark Determination.

A Contact Lens Optical Quality Analyzer (CLOQA) is developed to determine optical distortions caused by surface deformations and other defects in the contact lens, based on the principle of the Foucault knife-edge test. A person skilled in the art understands how to select, align and arrange various optics elements to create collimating light, to illuminate a contact lens, and to capture an image with a device (for example, such as, a CCD camera). The test involves illuminating the contact lens with a near-collimated light, placing a Foucault knife edge near the focal point, moving the knife-edge to block off most of the focused light, and capturing the image of contact lens with a device, for example CCD camera behind the Foucault knife edge. Where there is no optical distortion in the contact lens, all light rays passing through the contact lens come to focus at the knife edge and most of the well-focused light will be blocked off. For areas outside the optical zone which has no focusing function, the knife-edge will block the light from half of the lens to make it dark, while the other half appear bright. If the contact lens has no optical distortions in its optical zone, the whole optical zone will be uniformly dark or bright depending on how much light is blocked by the knife-edge. Where there are optical distortions on the contact lens, light passing through such areas in general does not fall into the main focus and may be either blocked by the knife edge (appearing dark) or pass through freely (appearing bright). The level of contrast not only depends on the amplitude of the distortion, but also depends on the fine position of the knife-edge. The defective areas appear as contrast features in the CLOQA image. The knife-edge test with CLOQA is designed as a qualitative testing device for optical distortions in the optical zone.

Folding mark study is carried out as follows. Three autoclaved and/or not autoclaved contact lenses are used in the study. First, images of the contact lenses are taken with the CLOQA. Second, each lens is folded with fingers twice (creating two perpendicular fold lines) and then its image is taken immediately with the CLOQA. Third, the image of each contact lens about 15 minutes after folding is taken with the CLOQA. Three types of CLOQA images are obtained: original one (i.e., without folding), immediately after folding, and about 15 minutes after folding. The folding mark study allows to determine the appearance of the folding line changing over time. 

What is claimed is:
 1. An amphiphilic siloxane-containing (meth)acrylamide, being represented by formula (1) or (2)

in which A₁, A₂, A₃ and A₄ independent of one another are a C₁-C₆ alkyl, phenyl or benzyl, r1 is an integer of 2 or 3, R′ is H or C₁-C₄ alkyl, R₁₀ is hydrogen or methyl, R₁₁ is a linear or branched C₂-C₆ alkylene divalent radical which may be substituted with one or more hydroxyl groups, R₁₂ is C₁-C₄ alkoxy, Z₁ and Z₂ independent of each another are a direct bond or a linear or branched C₁-C₄ alkylene divalent radical, Z₃ is C₂-C₄ alkylene divalent radical, Z₄, Z₅, and Z₆ independent of one another are a direct bond or a linear or branched C₁-C₂₀ alkylene divalent radical which may have one or more ether, thio, amine, carbonyl, or amido linkages in their main chain, X₁ is —O—CO—NH— or —O—CO—NH—R₁₃—NH—CO—O— in which R₁₃ is a linear or branched C₂-C₁₂ alkylene divalent radical or a C₅-C₄₅ cycloaliphatic or aliphatic-cycloaliphatic divalent radical, X₂ and X₃ independent of each other are selected from the group consisting of direct bond, —O—, —NR′—, —CO—NR′—, —NR′—CO—, —O—CO—NH—, —NH—CO—O—, —NR′—CO—NH—, —NH—CO—NR′—, —S—CO—NH—, —NH—CO—S—, —S—, —CO—O—, —O—CO—, —O—CO—NH—R₁₃—NH—CO—O—, and —NH—CO—NH—R₁₃—NH—CO—NH—, in which R′ and R₁₃ are as defined above, q1 is an integer from 2 to 50, q2 is an integer from 3 to
 20. 2. The amphiphilic siloxane-containing (meth)acrylamide of claim 1, being represented by formula (1) as defined in claim
 1. 3. The amphiphilic siloxane-containing (meth)acrylamide of claim 2, wherein R′ is hydrogen; R₁₀ is hydrogen or methyl; R₁₁ is a linear or branched C₂-C₆ alkylene divalent radical; R₁₂ is C₁-C₆ alkoxy; Z₁ and Z₂ are a direct bond; Z₃ is C₂-C₄ alkylene divalent radical; X₁ is —O—CO—NH— or —O—CO—NH—R₁₃—NH—CO—O— in which R₁₃ is a linear or branched C₂-C₁₂ alkylene divalent radical or a C₅-C₄₅ cycloaliphatic or aliphatic-cycloaliphatic divalent radical; q1 is an integer from 2 to
 50. 4. The amphiphilic siloxane-containing (meth)acrylamide of claim 1, being represented by formula (1) as defined in claim
 1. 5. The amphiphilic siloxane-containing (meth)acrylamide of claim 4, being represented by any one of formula (2a) to (2d)

in which: R₁₀ is hydrogen or methyl; R₁₁ is a linear or branched C₂-C₆ alkylene divalent radical; R₁₄ is —CH₂CH₂CH₂— or —CH₂CH(CH₃)—; X₄ and X₆ independent of each other are —O—, —NH—, —CO—NH—, —NH—CO—, —O—CO—NH—, —NH—CO—NH—, —CO—O—, —O—CO—, —S—, —O—CO—NH—R₁₃—NH—CO—O—, or —NH—CO—NH—R₁₃—NH—CO—NH— in which R₁₃ is a linear or branched C₂-C₁₂ alkylene divalent radical or a C₅-C₄₅ cycloaliphatic or aliphatic-cycloaliphatic divalent radical; X₅ is —NH—, —CO—NH—, —NH—CO—, —NH—CO—NH—, —CO—O—, —O—CO—, —S—, or —NH—CO—NH—R₁₃—NH—CO—NH— in which R₁₃ is as defined above; q2 is an integer from 2 to 50; n1 and n3 independent of each other are an integer from 1 to 3; n2 is an integer 2 or
 3. 6. The amphiphilic siloxane-containing (meth)acrylamide of claim 1, wherein the amphiphilic siloxane-containing (meth)acrylamide has a water solubility or dispersibility of at least about 5% by weight in water.
 7. A polymer comprising monomeric units derived from an amphiphilic siloxane-containing (meth)acrylamide of claim
 1. 8. The polymer of claim 7, wherein the polymer is an actinically-crosslinkable silicone-containing prepolymer which further comprises: (1) crosslinking units derived from at least one polysiloxane-containing crosslinker and/or at least one non-silicone crosslinker; (2) hydrophilic units derived from at least one hydrophilic vinylic monomer; (3) polymerizable units derived from a chain transfer agent having a first reactive functional group other than thiol group and/or a vinylic monomer having a second reactive functional group other than ethylenically-unsaturated group, wherein the polymerizable units each comprise an ethylenically unsaturated group covalently attached to one polymerizable unit through the first or second reactive functional group; and (4) optionally UV-absorbing units derived from a UV-absorbing vinylic monomer, wherein the prepolymer is capable of being actinically crosslinked, in the absence of one or more vinylic monomers, to form a silicone hydrogel contact lens having a water content of from about 20% to about 75% by weight when fully hydrated, and an oxygen permeability (Dk) of at least about 40 barrers.
 9. The polymer of claim 8, wherein the prepolymer has a high water solubility or dispersibility of at least about 5% by weight in water, wherein the crosslinking units are derived from at least one hydrophilized polysiloxane-containing crosslinker and/or at least one non-silicone hydrophilic crosslinker.
 10. A soft contact lens comprising a silicone hydrogel material comprising monomeric units derived from a hydrophilic vinylic monomer and monomeric units derived from an amphiphilic siloxane-containing (meth)acrylamide of claim 1, wherein the contact lens has a water content of from about 20% to about 75% by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers, and an elastic modulus of from about 0.1 MPa to about 2.0 MPa.
 11. A soft contact lens comprising a silicone hydrogel material obtained by curing a lens-forming material in a mold, wherein the lens-forming formulation comprises at least one hydrophilic vinylic monomer and at least one amphiphilic siloxane-containing (meth)acrylamide of claim 1, wherein the contact lens has a water content of from about 20% to about 75% by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers, and an elastic modulus of from about 0.1 MPa to about 2.0 MPa.
 12. The soft contact lens of claim 11, wherein the lens-forming formulation further comprises one or more components selected from the group consisting of a polysiloxane-containing crosslinker, a non-silicone crosslinker, a photoinitiator, a thermal initiator, a UV-absorbing inylic monomer, a visibility tinting agent, antimicrobial agents, a bioactive agent, leachable lubricants, leachable tear-stabilizing agents, and mixtures thereof.
 13. A soft contact lens comprising a silicone hydrogel material obtained by curing a lens-forming material in a mold, wherein the lens-forming formulation comprises at least one actinically-crosslinkable silicone-containing prepolymer of claim 8, wherein the contact lens has a water content of from about 20% to about 75% by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers, and an elastic modulus of from about 0.1 MPa to about 2.0 MPa.
 14. The soft contact lens of claim 13, wherein the lens-forming formulation further comprises one or more components selected from the group consisting of a polysiloxane-containing crosslinker, a non-silicone crosslinker, a photoinitiator, a thermal initiator, a UV-absorbing inylic monomer, a visibility tinting agent, antimicrobial agents, a bioactive agent, leachable lubricants, leachable tear-stabilizing agents, and mixtures thereof.
 15. A method for making silicone hydrogel contact lenses, comprising the steps of: introducing a lens-forming formulation into a mold for making contact lenses, wherein the lens-forming formulation comprises (a) a solvent selected from the group consisting of water, 1,2-propylene glycol, a polyethyleneglycol having a molecular weight of about 400 Daltons or less, and mixtures thereof, (b) at least one amphiphilic siloxane-containing (meth)acrylamide of claim 1, (c) at least one hydrophilic vinylic monomer, and (d) at least one component selected from the group consisting of a hydrophilized polysiloxane-containing crosslinker, a hydrophilic crosslinker, a photoinitiator, a thermal initiator, a UV-absorbing vinylic monomer, a visibility tinting agent, an antimicrobial agent, a bioactive agent, a leachable lubricant, a leachable tear-stabilizing agent, and mixtures thereof; polymerizing the lens-forming formulation in the mold to form a silicone hydrogel contact lens, wherein the formed silicone hydrogel contact lens has a water content of from about 20% to about 75% by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers, and an elastic modulus of from about 0.1 MPa to about 2.0 MPa.
 16. The method of claim 15, further comprising the step of extracting the molded silicone hydrogel contact lens with water or an aqueous solution.
 17. The method of claim 16, wherein the mold is a reusable mold and the lens-forming composition is cured actinically under a spatial limitation of actinic radiation to form the silicone hydrogel contact lens.
 18. A method for making silicone hydrogel contact lenses, comprising the steps of: introducing a lens-forming formulation into a mold for making contact lenses, wherein the lens-forming formulation comprises (a) a solvent selected from the group consisting of water, 1,2-propylene glycol, a polyethyleneglycol having a molecular weight of about 400 Daltons or less, and mixtures thereof, (b) at least one actinically-crosslinked silicone containing prepolymer of claim 8, and (c) at least one component selected from the group consisting of a hydrophilic vinylic monomer, a hydrophilized polysiloxane-containing crosslinker, a hydrophilic crosslinker, a photoinitiator, a thermal initiator, a UV-absorbing vinylic monomer, a visibility tinting agent, an antimicrobial agent, a bioactive agent, a leachable lubricant, a leachable tear-stabilizing agent, and mixtures thereof; polymerizing the lens-forming formulation in the mold to form a silicone hydrogel contact lens, wherein the formed silicone hydrogel contact lens has a water content of from about 20% to about 75% by weight when fully hydrated, an oxygen permeability (Dk) of at least about 40 barrers, and an elastic modulus of from about 0.1 MPa to about 2.0 MPa.
 19. The method of claim 18, further comprising the step of extracting the molded silicone hydrogel contact lens with water or an aqueous solution.
 20. The method of claim 19, wherein the mold is a reusable mold and the lens-forming composition is cured actinically under a spatial limitation of actinic radiation to form the silicone hydrogel contact lens. 